Digital microfluidic chip and digital microfluidic system

Abstract

A digital microfluidic chip and a digital microfluidic system. The digital microfluidic chip comprises: an upper substrate and a lower substrate arranged opposite to each other; multiple driving circuits and multiple addressing circuits disposed between the lower substrate and the upper substrate; and a control circuit, electrically connected to the driving circuits and the addressing circuits. The control circuit is configured to apply, in a driving stage, a driving voltage to each driving circuit, such that a droplet is controlled to move inside a droplet accommodation space according to a set path, measure, in a detection stage, after a bias voltage is applied to each addressing circuit, a charge loss amount of each addressing circuit, and to determine the position of the droplet according to the charge loss amount. The charge loss amount of each addressing circuit is related to the intensity of received external light.

The invention claimed is: 
     
       1. A digital microfluidic chip, comprising:
 an upper substrate and a lower substrate disposed oppositely; 
 a first hydrophobic layer disposed on a side surface of the lower substrate facing the upper substrate; 
 a second hydrophobic layer disposed on a side surface of the upper substrate facing the lower substrate, with a space between the first hydrophobic layer and the second hydrophobic layer forming a droplet accommodation space; and 
 a plurality of drive circuits and a plurality of addressing circuits, located between the lower substrate and the upper substrate, 
 wherein one of the plurality of addressing circuits corresponds to at least one of the plurality of drive circuits; 
 wherein each of the drive circuits comprises a driving electrode located between the lower substrate and the first hydrophobic layer, and a reference electrode located between the upper substrate and the second hydrophobic layer; 
 wherein each of the addressing circuits comprises a bottom electrode, a photoelectric conversion layer and a top electrode disposed in a stacked manner between the lower substrate and the first hydrophobic layer, wherein the bottom electrode is closer to the lower substrate than the top electrode, and the top electrode is a transparent electrode; 
 wherein a layer where the top electrode is located and the layer where the driving electrodes are located are a same film layer. 
 
     
     
       2. The digital microfluidic chip according to  claim 1 , wherein the reference electrodes of the plurality of drive circuits are connected to each other to form an integrated structure; and
 the digital microfluidic chip further comprises a first insulating layer between a layer where driving electrodes are located and the first hydrophobic layer, and a second insulating layer between a layer where the reference electrodes are located and the second hydrophobic layer. 
 
     
     
       3. The digital microfluidic chip according to  claim 1 , wherein the top electrode is connected with an adjacent one of the driving electrodes to form an integrated structure. 
     
     
       4. The digital microfluidic chip according to  claim 1 , wherein the layer where the top electrode is located is on a side facing the lower substrate, of the layer where the driving electrode is located; and an orthogonal projection of the top electrode on the lower substrate is at least partially covered by an orthographic projection of the driving electrode on the lower substrate. 
     
     
       5. The digital microfluidic chip according to  claim 1 , wherein each of the plurality of drive circuits further comprises a switching transistor between the lower substrate and the layer where the driving electrode is located, the switching transistor comprising a gate, a gate insulating layer, an active layer and a source-drain electrode which are stacked in that order on the lower substrate; and
 a third insulating layer is provided between the switching transistor and the layer where the driving electrode is located, and a drain of the source-drain electrode is connected to the driving electrode through a via hole running through the third insulating layer. 
 
     
     
       6. The digital microfluidic chip according to  claim 5 , wherein the digital microfluidic chip further comprises bias voltage signal lines electrically connected to the bottom electrodes; and
 the bottom electrodes are disposed in a same layer as the source-drains, and the bias voltage signal lines are disposed in a same layer as the gates. 
 
     
     
       7. A digital microfluidic system, comprising: the digital microfluidic chip according to  claim 1 , and a control circuit;
 wherein the control circuit is electrically connected to the drive circuits and the addressing circuits in the digital microfluidic chip, and the control circuit is configured to, in a driving stage, apply a driving voltage to each of the drive circuits to control a droplet to move according to a set path in the droplet storage space; and in a detection stage, detect an amount of charge loss of each of the addressing circuits after a bias voltage is applied to each of the addressing circuits, and determine a position of the droplet according to the amount of charge loss, wherein the amount of charge loss of each of the addressing circuits is related to an intensity of received external light. 
 
     
     
       8. The digital microfluidic system according to  claim 7 , wherein the control circuit is specifically configured to, in the driving stage, apply a driving voltage to a next drive circuit adjacent to the position of the droplet on the set moving path according to the determined position of the droplet so that the droplet moves along the set path. 
     
     
       9. The digital microfluidic system according to  claim 7 , wherein the control circuit comprises a gate drive circuit and a data drive circuit;
 gates of switching transistors in the digital microfluidic chip are electrically connected to the gate drive circuit through gate lines provided in a same layer as the gates, and sources of source-drains of the switching transistors are electrically connected to the data drive circuit through data lines provided in a same layer as the sources, and the bias voltage signal lines are electrically connected to the gate drive circuit or the data drive circuit. 
 
     
     
       10. A driving method of the digital microfluidic system according to  claim 7 , comprising:
 in a driving stage, applying a driving voltage to each of the plurality of drive circuits to control a droplet to move according to a set path in the droplet storage space; and 
 in a detection stage, detecting an amount of charge loss of each of the addressing circuits after a bias voltage is applied to each of the addressing circuits, and determining a position of the droplet according to the amount of charge loss, 
 wherein the amount of charge loss of each of the addressing circuits is related to an intensity of received external light. 
 
     
     
       11. The driving method according to  claim 10 , comprising:
 in the driving stage, applying a driving voltage to a next drive circuit adjacent to the position of the droplet on a set moving path according to the determined position of the droplet so that the droplet moves along the set path.